Super Hornet performance question

Military aircraft - Post cold war aircraft, including for example B-2, Gripen, F-18E/F Super Hornet, Rafale, and Typhoon.
  • Author
  • Message
Offline

haavarla

Banned

  • Posts: 873
  • Joined: 28 Jul 2009, 19:36

Unread post04 Dec 2011, 20:56

That was very productive.. :doh:
One liners like these should be banned.

It is well known that any modern PESA radar has about twice as fast scann over the same volume.
Like it or not it is just one of the compromises that goes into any modern AESA.
And the AN/APG-79 has an Fixed Array, while the Irbis-E can steer it all over, hense it can scann much more volum. And as any fixed array, it will also get limit range at the corners of the scann area.
Is this so hard to understand?
Offline

wrightwing

Elite 2K

Elite 2K

  • Posts: 2543
  • Joined: 23 Oct 2008, 15:22

Unread post04 Dec 2011, 21:46

haavarla wrote:That was very productive.. :doh:
One liners like these should be banned.

It is well known that any modern PESA radar has about twice as fast scann over the same volume.
Like it or not it is just one of the compromises that goes into any modern AESA.
And the AN/APG-79 has an Fixed Array, while the Irbis-E can steer it all over, hense it can scann much more volum. And as any fixed array, it will also get limit range at the corners of the scann area.
Is this so hard to understand?


2 issues here though.

It is a powerful radar, but will broadcast the position of the Flanker, from a considerable distance.

Being that it does have a gimballed antenna, at some point in the scan, it's going to present very reflective surfaces to an opponent. If you've noted, most AESA arrays are canted, so that the antenna doesn't provide a 90 degree angle to incoming radar beams.
Offline

haavarla

Banned

  • Posts: 873
  • Joined: 28 Jul 2009, 19:36

Unread post04 Dec 2011, 22:44

Well you are right about the canted issue.
However, i supose it can be done with the Irbis-E to some extend.
You just reflect it downward mechanical, and the ESA function will still be able to scann ahead.

http://www.youtube.com/watch?v=yELuKJFDM80

Perhaps it can be done in a more passive search mode though..
Offline

wrightwing

Elite 2K

Elite 2K

  • Posts: 2543
  • Joined: 23 Oct 2008, 15:22

Unread post05 Dec 2011, 15:18

haavarla wrote:Well you are right about the canted issue.
However, i supose it can be done with the Irbis-E to some extend.
You just reflect it downward mechanical, and the ESA function will still be able to scann ahead.

http://www.youtube.com/watch?v=yELuKJFDM80

Perhaps it can be done in a more passive search mode though..


Then the issue is that you lose the azimuth advantage, and you still have a large beacon, for ESM systems to pick up.
Offline

haavarla

Banned

  • Posts: 873
  • Joined: 28 Jul 2009, 19:36

Unread post05 Dec 2011, 22:25

Losing any 'additional' azimuth advantage is a small price to pay for reduced detection wouldn't you say. :thumb:

The Irbis-E radar have several of the same features as any LPI radar have, see below.

Many features distinguish LPI radar from conventional radar. These include:

Low sidelobe antennas,

Irregular antenna scan patterns,

High duty cycle/wide band transmission,

Accurate power management,

Carrier frequency,

Very high sensitivity,

High processing gain,

Coherent detection,

Monostatic/bistatic configurations.

And this is the most interesting notion that any LPI radar, in fact will not have any more sucssess than any powerful PESA radar:

2. Sensitivities Required for Jamming.

The process of coding the information onto the radar waveform and decoding it inthe receiver is 6dB less efficient than a typical communication channel, which may itself be assumed to be 6dB less efficient than the Shannon limit. Therefore, 48dB SNR is needed to recover the required information from the signal. This is approximately equivalent to removing the 30dB increase in sensitivity obtained by going from an IFMtype receiver to a matched ES receiver. It can be hypothesized that the channelized receiver achieves an intermediate exploitation performance by being less lossy than the IFM type receiver in recovering the information, but that it will require additional SNR tostitch together the outputs of the different channels to recover all the information required(Stove, Hume, and Baker 2004, 249-260).The results derived above show that it is possible to exploit the radar’s transmissions. The simple radiometric detector is able to cope with any waveform, but at the cost of destroying most of the information contained within it. This makes it unsuitable for use in a busy environment, but it can be useful during normal ‘radarsilence’ when very few emitters will be present. In fact, in busy environments, it can beargued that the best way of transmitting covertly is to make the transmissions look like acommercial radar, such as a conventional marine radar or aircraft weather radar. Thus, they may not be noticed.

So in a jammer rich inviroment, any LPI pattern is unsuiteble..
Last edited by haavarla on 06 Dec 2011, 07:56, edited 1 time in total.
Offline

thestealthfighterguy

Senior member

Senior member

  • Posts: 252
  • Joined: 15 Sep 2011, 01:18
  • Location: Your six-O-clock

Unread post06 Dec 2011, 02:00

Question? As I understand it PESA's have a harder time discriminating between targets flying in close formation. Is this true?

Also, someone said something about Russian radar range. Maybe these will help. Not all the ranges match as some are estimates.

Thanks. TSFG
Attachments
Rus-AESA-Params-2009-A.png
Russian radar range vs RCS Irbis-BARS.png
FA-22A-Radar-2004D.png
Stealth, so the bad guys don't know your there till they start blowing up. Have a nice day!
Offline

Thumper3181

Forum Veteran

Forum Veteran

  • Posts: 626
  • Joined: 23 Jun 2006, 05:49

Unread post06 Dec 2011, 06:48

haavarla wrote:Well you are right about the canted issue.
However, i supose it can be done with the Irbis-E to some extend.
You just reflect it downward mechanical, and the ESA function will still be able to scann ahead.

http://www.youtube.com/watch?v=yELuKJFDM80

Perhaps it can be done in a more passive search mode though..


Do some math before you start spouting off about things you read in sales brochures. Draw 120 degree angle (prototype Irbis E installation. Extend the lines out to 100km. Let me know if 1. Irbis E has ther processing power to scan all that sky and 2. Whether or not the jet will have enough fuel to change course and intercept any targets between 60 and 120 degrees assuming that target is doing anything other being on an intercept course. Hint, the answer to both questions is no.

The Russians know this as well. That is why the production (whenever that happens) Irbis E will be a fixed installation.
http://warfare.ru/?linkid=2568&catid=334

As for your LPI assertion, lets just say there are varying degrees of LPI and a PESA by it's very nature is not going to be very good at it. In simple terms a PESA can only transmit on a single frequency at a single point in time. So even if the frequency is jumping very quickly, the system is still pumping out X amount of KW's into the battlespace. therefore its LPI capability will always be limited. AESA's on the other hand transmit on over a thousand separate frequencies at any one time. So if a 1000T/R AESA is transmitting at 1kw, its only putting out 1 watt of EM energy at any point in time on any particular frequency. This makes them an order of magnitude more difficult to detect by RWR/ESM. Add to that IRBIS's huge power output (peak 21kw) on a single frequency and the LPI claim is a joke and you spouting off about it just confirms my suspicion that you haven't a clue and are merely regurgitating propaganda.

thestealthfighterguy, those range charts look like they came straight from APA. At any rate they are complete speculation and should be taken with a huge grain of salt. Power output does not directly correlate to detection much less tracking range.
Offline

haavarla

Banned

  • Posts: 873
  • Joined: 28 Jul 2009, 19:36

Unread post06 Dec 2011, 10:06

The Russians know this as well. That is why the production (whenever that happens) Irbis E will be a fixed installation.
http://warfare.ru/?linkid=2568&catid=334


Dude, you are using APA related stuff as a source?
Go to NIIP.ru
Official specs state the Irbis-E have a gimbal slated array.

The second Irbis-E are on the second serial Su-35S.
Here:
http://www.knaapo.ru/eng/gallery/aircra ... _su-35.wbp

The Irbis-E have lots of different mode, and what is the purpose of 4 four channel radar.
It means you can operate on mulitple modes at the same time.
Yes the search pattern is more focused on a PESA radar, but again the search pattern speed is much faster vs AESA radar.

Whenever an AESA are using its passive LPI mode in a heavy enviroment, it means the signal from any enemy(transmitting) signal will suffer signal distortion/degritation due to too much noise. It will have to change to a more active mode, meaning transmitting more power.
The LPI mode is the future roadmap to go, but it too has its limitations, as with every thing in aviation and avionics, pros & cons..

So what are you saying, that i can't use any official sales specs from NIIP, but you can use whatever comes out from Raytheon??
Nice double standard there.. and derby makes it impossible to dabate anything with you.
Offline

sprstdlyscottsmn

Elite 3K

Elite 3K

  • Posts: 3144
  • Joined: 10 Mar 2006, 01:24
  • Location: Phoenix, Az

Unread post06 Dec 2011, 14:43

Your missing the point about LPI though. Everything you state points to a very advanced radar. No one is disputing that. But What makes AESA better for LPI is that each TR module is its own radar that changes frequency with each transmission. If the environment is clean and only one TR is needed to do the job then only one is used. If more are needed then more are pointed in the same direction, but all at different frequencies. If the situation is so EM saturated that it wont work then it turns off and just listens. Having a gimbled PESA is nice for volume search, but it also means that while you are looking at the -120 through 0 degree area you are blind to the 1 through 120 degree area. It does allow it to fly 60 degrees off from where it is searching, but then exposes the biggest RCS reflectors it has toward it's scan zone, the 15 foot tall vertical stabs. Having a PESA that moves only gives it one advantage over AESA, wider azimuth, but still has the limit of PESA, every module fires at the same time and at the same frequency, even if they are going different directions for different tasks.
"Spurts"

-Pilot
-Aerospace Engineer
-Army Medic
-FMS Systems Engineer
Offline

haavarla

Banned

  • Posts: 873
  • Joined: 28 Jul 2009, 19:36

Unread post06 Dec 2011, 15:42

Well, i have never disputed that AESA do not have its advantage over any PESA radar.
I was only pointing out some limitation of AESA in LPI mode.. which i often see are misused on various forum as the ultimate bling bling to defeat any opposition party..

Question? As I understand it PESA's have a harder time discriminating between targets flying in close formation. Is this true?

Also, someone said something about Russian radar range. Maybe these will help. Not all the ranges match as some are estimates.

Thanks. TSFG


Yes, ultimatly an AESA radar will have more or higher resolution, and thus be able to see clearer, especialy in a busy enviroment.

However, PESA radars can use an mode in which they narrow the beam pattern. Mostly used if you know where to look(scann), be this in a Jammer rich enviroment or at extreme long range(BVR).
Works Even better If you have AWACS support and/or just network sentric between a group of fighters.

An AESA would simply put more Transmitters on the same area, and of course apply more power if needed.
Last edited by haavarla on 08 Dec 2011, 03:45, edited 2 times in total.
Offline

thestealthfighterguy

Senior member

Senior member

  • Posts: 252
  • Joined: 15 Sep 2011, 01:18
  • Location: Your six-O-clock

Unread post06 Dec 2011, 19:11

Thumper3181 wrote:thestealthfighterguy, those range charts look like they came straight from APA. At any rate they are complete speculation and should be taken with a huge grain of salt. Power output does not directly correlate to detection much less tracking range.


Yes. I know. That is why I said some are estimates. They even say est. on the charts. They are just to get a picture in your head. Although they are based on Russian data and you can ask Haav, I've said to him in the past, I always take Russian propaganda with a grain of salt. The U.S. aften "under" rates it's tech for tactical reasons well Russia often "over" rates for sales reasons. This is why I've said in the past "I'll belive it when I see it" about Russian specs.
TSFG
Stealth, so the bad guys don't know your there till they start blowing up. Have a nice day!
Offline

geogen

Banned

  • Posts: 3123
  • Joined: 11 Mar 2008, 15:28
  • Location: 45 km offshore, New England

Unread post08 Dec 2011, 09:03

Give me a 6-ship of F-18E+ w/CFT, ALQ-218(V)3 algorithmic-enhanced for aerial AESA geolocation, 280mm high-res LW IRST on the waist with a MALD-J on the other side, 3x AIM-174 (Tri-seeker) + 2x AIM-162 (IIR, mmW) and you will not want to be a 4-ship (2+2) consisting of F-22 and Su-35S in Red Flag 2017. Either with equivalent AWACS support or none. Back those babies off. :thumb:
The Super-Viper has not yet begun to concede.
Offline

haavarla

Banned

  • Posts: 873
  • Joined: 28 Jul 2009, 19:36

Unread post08 Dec 2011, 16:48

There are counter to everything.

Well then, i'll bring with me a quad formation of Mig-31BM.
That Zaslon-M radar will find those SH, and roast em before the Migs get into NEZ... :wink:

http://www.flightglobal.com/news/articl ... me-346177/

Or two Su-35S and two Mig-31BM.
The Migs could function as painters and the Su-35 with its L175M Khibiny-M electronic-warfare self-defense system could shaddow the Migs until they get target feed.
Then fire up the Irbis-E at full power and let ripp its ordinance and turn home.

Anyway, i'm sure if the F-22 could talk with the Su-35S in a network centric enviroment, they would be hard to defeat..
Last edited by haavarla on 08 Dec 2011, 17:17, edited 2 times in total.
Offline

wrightwing

Elite 2K

Elite 2K

  • Posts: 2543
  • Joined: 23 Oct 2008, 15:22

Unread post08 Dec 2011, 17:00

geogen wrote:Give me a 6-ship of F-18E+ w/CFT, ALQ-218(V)3 algorithmic-enhanced for aerial AESA geolocation, 280mm high-res LW IRST on the waist with a MALD-J on the other side, 3x AIM-174 (Tri-seeker) + 2x AIM-162 (IIR, mmW) and you will not want to be a 4-ship (2+2) consisting of F-22 and Su-35S in Red Flag 2017. Either with equivalent AWACS support or none. Back those babies off. :thumb:
Just a few observations- it's not just AESA that you're having to geolocate. It's LPI AESA signals. It's one thing if you already have APG-77 waveforms, in your digital library, but if you're starting from scratch, you're still going to have to deal with detection, identification, and trying to geolocate(remember, the shooter isn't necessarily the emitter). Secondly you're making some big assumptions on the effectiveness of the countermeasures vs. the F-22's systems(which may be conducting an EA themselves). Thirdly, while a F-22/Su-35 flight would be potent, if they had compatible datalinks, you'd be much better off with an AESA equipped F-15(and other associated mods, like IRST/Jammer). It's a bit optimistic to think that you'd get 2 new AIMs IOC by that time frame, seeing as how long it normally takes even to go from AIM-9M to AIM-9X Block II, or AIM-120C5 to AIM-120D. Lastly, seeing as how threat aircraft are known to have IRSTs, you have to assume that F-22 pilots practice tactics, which take this into consideration, not to mention reduced IR signatures.
Offline

tacf-x

Forum Veteran

Forum Veteran

  • Posts: 511
  • Joined: 17 Sep 2011, 02:25
  • Location: Champaign, Illinois

Unread post08 Dec 2011, 18:19

Why use a mmW seeker? Aren't those incapable of detecting and tracking things from far away in a less than ideal environment? I read about this idea from Key and a lot of people panned it due to the fact that the waveform would be easily absorbed by adverse weather.
PreviousNext

Return to Modern Military Aircraft

Who is online

Users browsing this forum: No registered users and 16 guests